SACRAMENT - Billionaire insurance executive George Joseph has donated another $8 million to his November ballot initiative.

The weekend contribution brings his total to $16 million in support of Proposition 33, which would let insurers charge drivers based on their history of maintaining coverage.

Joseph on Monday said campaign officials had asked for another $10 million, but he made a slightly smaller donation because he thought "with 16 or so million, you ought to be able to run a pretty good campaign."

The Mercury General Corp. chairman contributed the same amount to a similar initiative that was defeated two years ago. Opponents have raised about $100,000.

The initiative would allow insurers to lower rates for drivers who maintain insurance coverage and raise them for drivers who dropped coverage in the past.